• Incidence of cancer among female flight attendants: a meta-analysis.

      Tokumaru, Osamu; Haruki, Kosuke; Bacal, Kira; Katagiri, Tomomi; Yamamoto, Taisuke; Sakurai, Yutaka (2009-05-20)
      BACKGROUND: Airline flight personnel work in a unique environment with exposure to known or suspected carcinogens and mutagens including ionizing cosmic radiation. A meta-analysis was conducted to study whether the occupational exposure of female flight attendants (FA) increased their relative risk of cancer incidence. METHODS: A bibliographical computer search from 1966 to 2005 of cancer incidence cohort studies of female FA was performed. Combined relative risks (RRc) in cancer incidence were calculated by means of meta-analysis. RESULTS: RRc and 95% confidence interval (CI) for malignant melanoma and breast cancer in female FA were 2.13 (95% CI: 1.58-2.88) and 1.41 (1.22-1.62) (p < 0.0001). Excess risk was not significant for all-site cancer with RRc of 1.10 (0.99-1.21). CONCLUSIONS: The meta-analysis confirmed the significantly increased risks for malignant melanoma and breast cancer in female FA. Increased exposure to cosmic radiation during flight has been suggested as a potential occupational risk factor. Ultraviolet radiation exposure on board seems an unlikely occupational risk, but nonoccupational leisure time sun exposure is a possible risk factor. The etiology of the observed increase in incidence of some cancers remains controversial because assessment of possible confounders, especially nonoccupational exposure factors, has thus far been limited.
    • Differential expression of molecular markers in arsenic- and non-arsenic-related urothelial cancer.

      Hour, Tzyh-Chyuan; Pu, Yeong-Shiau; Lin, Chia-Chi; Huang, Shi-Wei; Chen, Jun; Chiu, Allen W.; Chen, Chien-Jen; Huang, Chao-Yuan (2009-05-15)
      BACKGROUND: Little is known about the mechanisms of arsenic-related urothelial cancer (AsUC). The aim of this study was to reveal the differential expression of molecular markers between AsUC and non-arsenic-related UC (non-AsUC). MATERIALS AND METHODS: Tissues of AsUC (n=33), non-AsUC (n=20) and normal bladder urothelia from patients with benign diseases (n=4) were examined for multiple selected molecular markers responsible for various cellular functions, includingglutathione, GST-pi, Bcl-2, p53 and c-Fos. RESULTS: The mean cellular glutathione content of normal mucosal samples (33.4 +/- 7.2 microM/mg protein) was significantly higher than either non-AsUC (22.8 +/- 1.8, p = 0.04) or AsUC (16.4 +/- 1.6, p = 0.002). The glutathione content of non-AsUC was higher than that of AsUC (p = 0.012). The expressions of Bcl-2 and c-Fos in AsUC were significantly higher than those in non-AsUC (p = 0.004 and p = 0.02, respectively). CONCLUSION: The carcinogenic pathway for AsUC is different, in part, from that of non-AsUC. Cellular glutathione contents may be down-regulated during urothelial carcinogenesis. Bcl-2 and c-Fos may play important roles in arsenic-mediated carcinogenesis of the urothelium.
    • Cytological value of sputum in workers daily exposed to air pollution.

      Alderisio, Mauro; Cenci, Maria; Mudu, Pierpaolo; Vecchione, Aldo; Giovagnoli, Maria Rosaria (2009-05-15)
      In this study, quantitative modifications of dust cells, siderocytes, Curschmann's spirals and asbestos bodies and qualitative modifications (cellular changes and inflammatory infiltrate) in the sputum of 164 traffic police officers and 218 railway workers, occupationally exposed to environmental pollution, and the sputum of 119 inhabitants of a rural area, were evaluated. The results were correlated with time of exposure and smoking habits. Seventy-three (45%) traffic police officers (TPO), 76 (35%) railway workers (RW) and 29 (24%) of the rural population (RP) were smokers. The sputum, collected over a 3-day period, was smeared on glass slides and stained according to the Papanicolaou, Perl and yellow eosin methods. The results of the qualitative cytological diagnosis revealed a statistically significant difference between the TPO, RW and the RP (p < 0.001). The results of the qualitative and quantitative cytological examinations were not significantly correlated to time of occupational exposure, which was considered to be a continuous variable. The qualitative cytological examination of sputa was not statistically significant for the smoking habits of the TPO and the RP, but was significant for the RW (p < 0.0067). In the TPO, the number of dust cells was higher in smokers, and the relative risk (RR) was 3.95. In the RW, the RR was 2.84. The results of our study revealed that for the RW, the qualitative-quantitative cytological alterations in sputum were due much more to smoking habits than to occupational exposure, while the presence of asbestos bodies correlated with work activity. The qualitative-quantitative cytological examinations of the TPO differed significantly from that of the other two populations.
    • CYP1A1 gene polymorphism and risk of endometrial hyperplasia and endometrial carcinoma.

      Esinler, I.; Aktas, D.; Alikasifoglu, M.; Tuncbilek, E.; Ayhan, A. (2009-03-18)
      The cytochrome P4501A1 (CYP1A1) is involved in the metabolism of environmental carcinogens and estrogen. We hypothesized that CYP1A1 genetic polymorphism may be a susceptibility factor for endometrial hyperplasia (EH) and endometrial carcinoma (ECa). We therefore evaluated this hypothesis in patients with EH and ECa and control subjects using allele-specific polymerase chain reaction-based method in a Turkish population. The patients with CYP1A1 Ile/Val genotype had a fivefold higher risk of having EH than those with Ile/Ile. In contrast, a higher frequency of any Val genotype (Ile/Val and Val/Val) was found in patients with EH, indicating that persons carrying any Val allele are at increased risk for developing EH. In the ECa group, patients were also more likely to have CYP1A1 Ile/Val allele, with an adjusted odds ratio of 3.0. Moreover, there was a statistically significant increase in relative risk association with any Val genotype between patients and controls, suggesting that individuals carrying any Val genotype are at increased risk for developing ECa. We concluded that variant alleles of the CYP1A1 gene might be associated with EH and ECa susceptibility. Further studies with a large sample size should be considered to address issues of interactions between CYP1A1 and other risk factors.
    • Active and passive smoking and risk of ovarian cancer.

      Baker, J. A.; Odunuga, O. O.; Rodabaugh, K. J.; Reid, M. E.; Menezes, R. J.; Moysich, K. B. (2009-03-18)
      It is unclear whether smoking is a risk factor for epithelial ovarian cancer, although some studies have suggested that it may be associated with an increased risk of mucinous tumors. This study investigated the effect of smoking and environmental tobacco smoke (ETS) on ovarian cancer risk among 434 women with primary epithelial ovarian, peritoneal, or fallopian cancers and 868 age- and region-matched hospital controls with nonneoplastic conditions. All participants completed a comprehensive epidemiologic questionnaire. Results indicate that decreased risk of ovarian cancer was associated with being a nonsmoker exposed to ETS (adjusted odds ratio [aOR] 0.68, 95% confidence interval [CI] 0.46-0.99), a former smoker (aOR 0.76, 95% CI 0.53-1.10), or a current smoker (aOR 0.53, 95% CI 0.32-0.88). A similar protective effect was noted for smokers with moderate or high exposure based on smoking intensity, duration, and cumulative exposure, as well as for never smokers exposed to ETS. Results did not differ substantially by histologic subtype. Although prevailing theories of ovarian cancer etiology implicate incessant ovulation, characteristics of the study population suggest that anovulation was not the protective mechanism in this study. Immunosuppression by nicotine or upregulation of enzymes that metabolize carcinogens may be responsible for the effects observed.
    • Tea-induced apoptosis in human leukemia K562 cells as assessed by comet formation.

      Chakraborty, Sutapa; Kundu, Trina; Dey, Subhabrata; Bhattacharya, Rathin K.; Siddiqi, Maqsood; Roy, Madhumita (2009-03-16)
      Programmed cell death or apoptosis is a physiological process by which genetically damaged cells or undesired cells can be eliminated. Various morphological and molecular changes undergoing during the process of apoptosis are the formation of apoptotic blebs of the cell membrane, cell shrinkage, condensation of chromatin and the disruption of deoxyribonucleic acid (DNA) into typical fragments of multiples of 180 base pairs. These changes can be detected in a number of ways. DNA ladder formation, which is observed following gel electrophoresis technique although is widely accepted but does not reflect the DNA breakdown in individual cell and also may miss contributions from small sub-populations in a heterogeneous cell population. Alkaline comet assay as measured by single cell gel electrophoresis, on the other hand, accurately measures DNA fragmentation on a single cell level and allows analysis of subpopulation of cells. The assay was originally developed for measuring DNA damage of cells exposed to any genotoxic agent. However, the comet image generated by an apoptotic cell is different from that obtained with a cell treated for a short time with a genotoxic agent. Correlation of comet formation with various other established parameters of apoptosis is very important. The present study aims to correlate different features of apoptosis with the formation of comet tail in human leukemia K-562 cells using tea extracts. Apoptosis as measured by formation of apoptotic bodies, flow cytometric analysis, activation of caspase 3 and 8, and expressions of apoptosis related genes such as bcl-2 and bax showed high degree of correlation with comet tail moment. This indicates that comet assay can accurately reflect measure of DNA fragmentation and hence can be used to detect a cell undergoing apoptosis.
    • Lack of promoting effects of phenobarbital at low dose on diethylnitrosamine-induced hepatocarcinogenesis in TGF-alpha transgenic mice.

      Puatanachokchai, Rawiwan; Kakuni, Masakazu; Wanibuchi, Hideki; Kinoshita, Anna; Kang, Jin Seok; Salim, Elsayed I.; Morimura, Keiichirou; Tamano, Seiko; Merlino, Glenn T.; Fukushima, Shoji (2009-03-16)
      Phenobarbital (PB), a rodent non-genotoxic carcinogen, showed hormesis, biphasic effects on rat liver carcinogenesis. To test the hypothesis that the hormesis earlier observed for PB induced hepatocarcinogenesis might also exist in the TGF-alpha transgenic mice model, one which is highly susceptible to carcinogenesis, the carcinogenic or promotion effects of a wide range of phenobarbital (PB) concentrations were investigated. Two weeks after a single i.p. dose of 5 mg /kg bw of diethylnitrosamine (DEN) to 15 day old mice, animals were treated with diet containing PB at doses of 0, 2, 15 or 500 ppm. The incidence and multiplicity of tumors, including hepatocellular adenomas and carcinomas, were significantly increased by the high dose of PB, but no significant difference among the groups receiving 2 and 15 ppm for liver tumors when compared to DEN alone group. The proliferating cell nuclear antigen indices for liver tumors and surrounding hepatocytes in high dose PB treated mice were significantly increased, but no change was noted at the lower doses. The total cytochrome P450 content in the liver was also elevated by 500 ppm of PB, while hepatic 8-OHdG levels demonstrated no significant change. In conclusion, PB at high dose enhances DEN-induced hepatocarcinogenesis in TGF-alpha transgenic mice, but low doses lack any significant effects. One possible mechanism of phenobarbital carcinogenicity might be influenced by cytochrome P450 system exhibiting a strong promoting activity for liver of mice.
    • Rapid analysis of XRCC1 polymorphisms using real-time polymerase chain reaction.

      Schneider, Joachim; Classen, Vera; Philipp, Monika; Helmig, Simone (2009-03-13)
      DNA repair plays a critical role in protecting the genome from carcinogens or ionizing radiation. Three coding polymorphisms at codons 194, 280, and 399 in X-ray cross-complementing group 1 (XRCC1) DNA repair gene have been identified that may affect DNA repair and alter cancer susceptibility. In order to study their role in molecular-epidemiology studies we developed a single-step procedure for genotyping these polymorphisms using real-time polymerase chain reaction (rt-PCR) and subsequent melting curve analysis. Genotypes of 622 unrelated Caucasians without prior history of cancer were determined by real-time PCR and compared to genotypes obtained by restriction fragment length polymorphism PCR. In the population studied, the allele frequency of the XRCC1 26304 site (C-->T) of codon 194 in exon 6 was 0.065, the allele frequency of the XRCC1 27466 site (G-->A) of codon 280 in exon 9 was 0.048 and of the XRCC1 28152 site (G-->A) of codon 399 in exon 10 was 0.35. There was no disagreement between the two methods. These findings confirm the real-time fluorescence PCR method as a rapid and reliable assay for the analysis of large numbers of samples.
    • Genetic variation of GSTM1, GSTT1 and GSTP1 genes in a South Indian population.

      Vettriselvi, V.; Vijayalakshmi, K.; Solomon Fd, Paul; Venkatachalam, P. (2009-03-11)
      The glutathione S transferase (GST) family of enzymes play a vital role in the phase II biotransformation of environmental carcinogens, pollutants, drugs and other xenobiotics. GSTs are polymorphic and the polymorphisms in GST genes have been associated with cancer susceptibility and prognosis. Moreover, distinct ethnic differences have been observed in the type and frequency of GST gene polymorphisms. Hence, the present study was aimed to determine the frequencies of GSTM1, GSTT1 and GSTP1 polymorphisms in 255 healthy random volunteers from South India. The GSTM1 and GSTT1 genotypes were determined by PCR and GSTP1 by PCR-RFLP using peripheral blood DNA.The GSTM1 and GSTT1 null genotype frequencies were found to be 22.4% and 17.6% respectively. The GSTP1 allelic frequency was 0.78 for the Ile allele and 0.22 for the Val allele and the genotype frequency was 58.4% for Ile/Ile, 38.4% for Ile/Val, and 3.1% for Val/Val. Comparison of the frequencies of GST polymorphisms observed in the present study with other Indian and world populations revealed a distinctive nature of the South Indian population with respect to polymorphims at the GST gene loci. A better understanding of carcinogen metabolizing gene distribution should contribute to risk assessment of humans exposed to environmental carcinogens.
    • Modifying effect of dietary sesaminol glucosides on the formation of azoxymethane-induced premalignant lesions of rat colon.

      Sheng, HongQiang; Hirose, Yoshinobu; Hata, Kazuya; Zheng, Qiao; Kuno, Toshiya; Asano, Nami; Yamada, Yasuhiro; Hara, Akira; Osawa, Toshihiko; Mori, Hideki (2007-02-08)
      Sesame, which has been reported to have preventive effects against various disordered conditions, contains small quantities of lignans and several precursors to them such as sesaminol glucosides (SG). The lignans have the potent antioxidative activity and are suggested to have chemopreventive property. In the present study, we evaluated the modulating effect of SG on the development of colon precancerous lesions, aberrant crypt foci (ACF) and beta-catenin-accumulated crypts (BCAC), in the azoxymethane (AOM)-induced short-term model using male F344 rats. Dietary SG (500 ppm) significantly decreased the incidence of AOM-induced ACF when compared to the control (P<0.01). The incidences of AOM-induced BCAC in the SG-treated groups (250 or 500 ppm) were also significantly lower than that of the control group (P<0.01). Interestingly, administration of 500 ppm SG clearly decreased serum triglyceride level and mRNA expression of intestinal fatty acid-binding protein in the colonic mucosa, as compared to the control. These findings indicate that dietary SG inhibits AOM-induced carcinogenesis and suggest SG as a possible chemopreventive agent.
    • Cytochrome P450 1B1, a novel chemopreventive target for benzo[a]pyrene-initiated human esophageal cancer.

      Wen, Xia; Walle, Thomas (2007-02-08)
      Esophageal cancer is common worldwide, with poor prognosis. Smoking, including exposure to polyaromatic hydrocarbons like benzo[a]pyrene (BaP), is a major risk factor. In human esophageal HET-1A cells, we found that time-dependent BaP-DNA binding was associated with upregulation of CYP1B1, but not CYP1A1, mRNA and protein. The dietary flavonoid 5,7-dimethoxyflavone significantly inhibited BaP-DNA binding and down-regulated BaP-induced CYP1B1 mRNA and protein. 3',4'-Dimethoxyflavone was an even more potent inhibitor of CYP1B1 expression, while resveratrol had no effect. Thus, dietary methoxylated flavones inhibited BaP-induced CYP1B1 transcription in a cell-specific manner and hold promise as chemopreventive agents in esophageal carcinogenesis.
    • Effect of urban traffic, individual habits, and genetic polymorphisms on background urinary 1-hydroxypyrene excretion.

      Cocco, Pierluigi; Moore, Patrick S.; Ennas, Maria G.; Tocco, Maria G.; Ibba, Antonio; Mattuzzi, Silvia; Meloni, Michele; Monne, Maria; Piras, Giovanna; Collu, Stefania; Satta, Giannina; Zucca, Mariagrazia; Scarpa, Aldo; Flore, Costantino (2007-01)
      PURPOSE: Potential sources of exposure to polycyclic aromatic hydrocarbons (PAHs) and genetic polymorphisms were investigated in relation to their contribution to interindividual variation in baseline levels of urinary 1-hydroxypyrene (1-OHP) excretion in subjects without occupational exposure to PAHs. METHODS: Urinary excretion of 1-OHP was measured in 114 subjects, including 48 women and 66 men. Questionnaire information was collected on possible environmental and individual sources of PAH exposure. A subset of 70 individuals also was evaluated for a single-nucleotide polymorphism (Ex7+295C-->T) in the cytochrome P-450 1A2 (CYP1A2) gene, and 61 of these also were evaluated for the glutathione transferase T1 (GSTT1) gene polymorphism. RESULTS: 1-OHP values did not show a significant seasonal variability and were unaffected by age; education; body mass index; smoking status, including passive smoking; or the C-->T base substitution in position 295 of exon 7 of the CYP1A2 gene. After reciprocal adjustment with logistic regression, living in a heavily trafficked urban area (odds ratio, 4.9; 95% confidence interval, 1.0-24.9), and frequent intake of grilled meat (odds ratio, 6.9; 95% confidence interval, 1.1-43.5) were significant predictors of background urinary 1-OHP levels of 0.50 microg/g creatinine or greater. Elevated risks also were associated with daily alcohol intake greater than 65 g and the nonnull GSTT1 genotype. CONCLUSION: Our study shows that exposure to urban traffic, dietary habits, and the nonnull GSTT1 genotype may contribute to interindividual variation in background levels of 1-OHP urinary excretion in subjects without occupational exposure to PAHs.
    • Phenylethyl isothiocyanate and its N-acetylcysteine conjugate suppress the metastasis of SK-Hep1 human hepatoma cells.

      Hwang, Eun-Sun; Lee, Hyong Joo (2006-12)
      Phenylethyl isothiocyanate (PEITC), a hydrolysis compound of gluconasturtiin, is metabolized to N-acetylcysteine (NAC)-PEITC in the body after the consumption of cruciferous vegetables. We observed an inhibitory effect of PEITC and its metabolite NAC-PEITC on cancer cell proliferation, adhesion, invasion, migration and metastasis in SK-Hep1 human hepatoma cells. PEITC and NAC-PEITC suppressed SK-Hep1 cell proliferation in a dose-dependent manner, and exposure to 10 microM PEITC or NAC-PEITC reduced cell proliferation by 25% and 30%, respectively. NAC-PEITC inhibited cancer cell adhesion, invasion and migration to a similar or to an even larger degree than PEITC. The expression of matrix metalloproteinase (MMP) 2, MMP-9 and membrane type 1 matrix metalloproteinase (MT1-MMP) is a known risk factor for metastatic disease. Gelatin zymography analysis revealed a significant downregulation of MMP-2/MMP-9 protein expression in SK-Hep1 cells treated with 0.1-5 microM PEITC or NAC-PEITC. PEITC and NAC-PEITC treatment caused dose-dependent decreases in MMP-2/MMP-9 and MT1-MMP mRNA levels, as determined by reverse transcription polymerase chain reaction. PEITC and NAC-PEITC also increased the mRNA levels of tissue inhibitors of matrix metalloproteinase (TIMPs) 1 and 2. Our data suggest that this inhibition is mediated by downregulation of MMP and upregulation of TIMPs.
    • Differential modulation of cyclooxygenase-mediated prostaglandin production by the putative cancer chemopreventive flavonoids tricin, apigenin and quercetin.

      Al-Fayez, Mohammad; Cai, Hong; Tunstall, Richard; Steward, William P.; Gescher, Andreas J. (2006-12)
      OBJECTIVES: Diet-derived flavonoids possess cancer chemopreventive properties in preclinical models. The knowledge of the pharmacology of most flavonoids is insufficient to warrant their advancement to clinical evaluation. METHODS: Here the three flavonoids tricin from rice bran, apigenin from leafy vegetables, and quercetin from onions and apples, were compared in terms of their ability to modulate cyclooxygenase- (COX-) catalyzed prostaglandin E-2 (PGE-2) generation. Specifically their effects on the following parameters were studied: (1) COX enzyme activity, (2) COX-2 expression in human-derived colon cancer cells HCA-7, which express COX-2 constitutively, (3) phorbol ester-mediated COX-2 induction in human colon epithelial cells (HCEC), and (4) PGE-2 levels in cellular incubations. RESULTS: Tricin and quercetin inhibited enzyme activity in purified COX-1 and -2 preparations with IC50 values of near 1 (tricin) and 5 microM (quercetin). Apigenin at up to 25 microM did not affect COX enzyme activity. Flavonoids were incubated with cells for 6 or 24 h and COX-2 protein expression and PGE-2 levels were assessed by Western blot and competitive immunoassay, respectively. None of the agents affected constitutive COX-2 expression in HCA-7 cells. Apigenin, but not tricin or quercetin, down-regulated inducible COX-2 expression in HCEC cells on 6 h incubation. All three flavonoids reduced cellular levels of PGE-2 in the supernatant of HCA-7 cells at both time points and of HCEC cells at 6 h. CONCLUSIONS: The results demonstrate that these structurally similar flavonoids regulate COX-mediated PGE-2 production in different fashions. Their ability to attenuate prostanoid levels may contribute to their cancer chemopreventive efficacy.
    • 9-cis-Retinoic acid inhibition of lung carcinogenesis in the A/J mouse model is accompanied by increased expression of RAR-beta but no change in cyclooxygenase-2.

      Mernitz, Heather; Smith, Donald E.; Zhu, Andrew X.; Wang, Xiang-Dong (2006-11-28)
      9-cis-Retinoic acid (9cRA) binds both retinoic acid receptors (RARs) and retinoid X receptors (RXRs) and has been shown to be a potential chemopreventive agent both in lung cancer cell culture studies and in clinical trials studying former smokers. However, direct evidence of the efficacy of 9cRA against lung tumor development in vivo is lacking. In the present study, we determined whether treatment with 9cRA has the potential to inhibit lung carcinogenesis by upregulating RAR-beta and down-regulating COX-2 expression in the A/J mouse lung cancer model. A/J mice (n=14-15/group) were treated as follows: (1) Control (Sham treated); (2) NNK (100mg NNK/kg body weight); (3) NNK+9cRA (15mg/kg diet); and (4) NNK+celecoxib (a COX-2-specific inhibitor, 500mg/kg diet). Tumor incidence, tumor multiplicity, RAR-beta mRNA, COX-2 mRNA, and COX-2 protein levels in lung samples of mice were determined 4 months after carcinogen injection. The results showed that mice receiving 9cRA supplementation had significantly lower tumor multiplicity (48% reduction, P<0.05) and showed a trend toward lower tumor incidence (40% reduction, P=0.078), as compared with the mice given NNK alone. Although, celecoxib treatment resulted in greater declines in tumor incidence and tumor multiplicity (75 and 88%, respectively, P<0.05), the chemoprotective effects of celecoxib were accompanied by increased mortality while 9cRA treatment resulted in no weight-loss associated toxicity or mortality. Supplementation with 9cRA was effective in increasing RAR-beta mRNA, but this increase was not accompanied by decreased levels of COX-2 mRNA or protein. These results suggest that 9cRA supplementation may provide protection against lung carcinogenesis and this effect may be mediated in part by 9cRA induction of RAR-beta, but not inhibition of COX-2 transcription.
    • Induction of aberrant crypt foci in DNA mismatch repair-deficient mice by the food-borne carcinogen 2-amino-1-methyl-6-phenylimidazo [4,5-b] pyridine (PhIP).

      Smith-Roe, Stephanie L.; Löhr, Christiane V.; Bildfell, Robert J.; Fischer, Kay A.; Hegan, Denise Campisi; Glazer, Peter M.; Buermeyer, Andrew B. (2006-11-28)
      Disruption of the DNA mismatch repair (MMR) pathway results in elevated mutation rates, inappropriate survival of cells bearing DNA damage, and increased cancer risk. Relatively little is known about the impact of environmentally relevant carcinogens on cancer risk in individuals with MMR-deficiency. We evaluated the effect of MMR status (Mlh1(+/+) versus Mlh1(-/-)) on the carcinogenic potential of the cooked-meat mutagen, 2-amino-1-methyl-6-phenylimidazo [4,5-b] pyridine (PhIP) in mice. PhIP exposure did not obviously increase lymphoma or small intestinal tumorigenesis in either Mlh1-deficient or -proficient mice. In contrast, the frequency of aberrant crypt foci (ACF), a preneoplastic biomarker for colon tumorigenesis, was increased by PhIP, and the increase due to PhIP was significantly greater in Mlh1(-/-) versus wild-type littermates. This apparent heightened susceptibility to induction of ACF parallels the previously reported hypermutability of Mlh1-deficient mice to PhIP and is consistent with the hypothesis that MMR-deficiency would increase the likelihood of PhIP-induced carcinogenic mutations. Further evaluation of the risk that consumption of heterocyclic amines may impart to MMR-deficient individuals therefore is warranted.
    • Environmental arsenic exposure and sputum metalloproteinase concentrations.

      Josyula, Arun B.; Poplin, Gerald S.; Kurzius-Spencer, Margaret; McClellen, Hannah E.; Kopplin, Michael J.; Stürup, Stefan; Clark Lantz, R.; Burgess, Jefferey L. (2006-11)
      Exposure to arsenic in drinking water is associated with an increased rate of lung cancer. The objective of this study was to determine whether arsenic exposure at relatively low concentrations (approximately 20 microg/L) is associated with changes in biomarkers of lung inflammation, as measured by the ratio of sputum metalloproteinase and antiproteinase activity. A total of 73 subjects residing in Ajo and Tucson, Arizona were recruited for this cross-sectional study. Tap water and first morning void urine were analyzed for arsenic. Matrix metalloproteinase 2 (MMP-2), 9 (MMP-9) and tissue inhibitor of metalloproteinase 1 (TIMP-1) were measured in induced sputum. Household tap water arsenic levels in Ajo (20.3+/-3.7 microg/L) were higher than in those Tucson (4.0+/-2.3 microg/L), as were mean urinary total inorganic arsenic levels (29.1+/-20.4 and 11.0+/-12.0 microg/L, respectively). Log-normalized MMP-2, MMP-9, and TIMP-1 concentrations in sputum were not significantly different between towns. However, after adjusting for town, asthma, diabetes, urinary monomethylarsonic acid/inorganic arsenic, and smoking history, total urinary arsenic was negatively associated with MMP-2 and TIMP-1 levels in sputum and positively associated with the ratio of MMP-2/TIMP-1 and MMP-9/TIMP-1 in sputum. Increased sputum proteinase/antiproteinase activity suggests a potential toxic mechanism for low-level arsenic exposure.
    • Polymorphisms and haplotypes of the NBS1 gene are associated with risk of sporadic breast cancer in non-Hispanic white women <or=55 years.

      Lu, Jiachun; Wei, Qingyi; Bondy, Melissa L.; Li, Donghui; Brewster, Abenaa; Shete, Sanjay; Yu, Tse-Kuan; Sahin, Aysegul; Meric-Bernstam, Funda; Hunt, Kelly K.; Singletary, S. Eva; Ross, Merrick I.; Wang, Li-E (2006-11)
      DNA double-strand breaks (DSBs) may lead to genomic instability and cancer if unrepaired. Nijmegen breakage syndrome 1 (NBS1) protein is one of the key proteins that participates in recognition and repair of DSBs in humans. We hypothesized that polymorphisms of NBS1 are associated with breast cancer risk. We selected three NBS1 haplotype-tagging polymorphisms (i.e. 924T>C, 8360G>C and 30537G>C) to represent all common (>or=5%) haplotypes reported in the National Institute of Environmental Health Sciences database and to reconstruct haplotypes. In a hospital-based case-control study of 421 non-Hispanic white patients with sporadic breast cancer (C polymorphism. Furthermore, the derived haplotypes were associated with risk in a dose-response manner as the number of variant (risk) alleles (i.e. 8360C, 924C or 30537C) increased (adjusted OR = 1.07, 95% CI = 0.78-1.46 for 1-2 variant alleles; adjusted OR = 2.47, 95% CI = 1.48-4.14 for 3-6 variant alleles; P(trend) = 0.006). These findings suggest that NBS1 polymorphisms and haplotypes may contribute to the etiology of sporadic breast cancer in young non-Hispanic white women. Large studies are warranted to confirm these findings.
    • International studies of prenatal exposure to polycyclic aromatic hydrocarbons and fetal growth.

      Choi, Hyunok; Jedrychowski, Wieslaw; Spengler, John; Camann, David E.; Whyatt, Robin M.; Rauh, Virginia; Tsai, Wei-Yann; Perera, Frederica P. (2006-11)
      OBJECTIVES: Polycyclic aromatic hydrocarbons (PAHs) are ubiquitously distributed human mutagens and carcinogens. However, lack of adequate air monitoring data has limited understanding of the effects of airborne PAHs on fetal growth. To address this gap in knowledge, we examined the association between prenatal exposure to airborne PAHs and birth weight, birth length, and birth head circumference, respectively, in Krakow, Poland, and New York City (NYC). METHODS: The parallel prospective cohort studies enrolled nonsmoking, healthy, and nonoccupationally exposed women and their newborns. Personal air monitoring of pregnant women was conducted over 48 hr. To control for maternal environmental tobacco smoke (ETS) exposure, we excluded those with umbilical cord plasma cotinine concentrations > 25 ng/mL. Mean cord plasma cotinine concentrations in both ethnic groups were
    • Red palm oil suppresses the formation of azoxymethane (AOM) induced aberrant crypt foci (ACF) in Fisher 344 male rats.

      Boateng, J.; Verghese, M.; Chawan, C.B.; Shackelford, L.; Walker, L.T.; Khatiwada, J.; Williams, D.S. (2006-10)
      Red palm oil (RPO) contains significant levels of carotenoids and Vitamin E. In this experiment we compared the inhibitory effects of RPO (7% and 14% levels) and soybean oil (7% and 14%) on azoxymethane (AOM) induced aberrant crypt foci (ACF). Thirty-two male Fisher 344 rats were randomly assigned to four groups. Two groups received AIN-93 G control (C) diet containing 7% and 14% soybean oil (SBO), respectively. Groups 3 and 4 received a treatment diet consisting of 7% and 14% RPO, respectively. The rats received subcutaneous injections of AOM at 16 mg/kg body weight at 7 and 8 weeks of age. At 17 weeks of age rats were killed by CO(2) asphyxiation. Numbers of ACF (mean+/-SE) in the proximal and distal colon were: 39.9 +/- 0.9, 53.8 +/- 2.8, 26.0 +/- 3.0, 27.5 +/- 1.5 and 118.2 +/- 1.7, 125.6 +/- 3.2, 41 +/- 7, 52.3 +/- 1.8 in rats fed 7% SBO, 14% SBO, 7% RPO and 14% RPO, respectively. The results of this study showed that RPO reduced the incidence of AOM induced ACF and may therefore have a beneficial effect in reducing the incidence of colon cancer.